HiDrive uses the Personal, Common, and Shared items in the left menu bar to manage user access to HiDrive data. This article explains the differences among these options.
Common (formerly "Public")
This menu item lists the objects that can be accessed by several people. Access permissions can be assigned separately for each folder and file. A folder share applies to all files in that folder. The article Using Shared Folders tells you about all of the management options.
Please note that the menu item Common was labeled as Public before July 2020.